Dial illuminating radio tube



Aug. 20, 1940- M. R. SCHULTE DIAL ILLUMINATING' RADIO TUBE Filed Jan. 20, 1939 m n mm W5 0 N. w N 4, mm

Patented Aug. 20, 1940 UNITED STATES PATENT OFFICE DIAL ILLUMINATING RADIO TUBE Application January 20, 1939, Serial N0. 251,876

Claims.

The invention relates to electronic devices, and more particularly radio tubes.

The object of the invention is generally a tube of this character having incorporated therein 5 a source of light so positioned as to be usable as a dial illuminating means and s0 connected with the tube element as to function during operation of the tube and without interference with the normal functioning of the tube. The inven- 3 tion thus makes possible the omission in a radio.

- set of the small separate light bulbs heretofore required for illumination of the dial and also of the necessary circuit connections.

Other objects of the invention will hereinafter appear.

For an understanding of the invention reference may be had to the accompanying drawing of which Fig. 1 is a side View of a radio tube embodying the invention;

Fig. 2 is an enlarged fragmentary view of the central portion of tube of Fig. 1 taken at right angles to the view of Fig. 1; and

Fig. 3 is a view of a modification.

26 Referring to the drawing, the radio tube en velope 2 is of a conventional shape which encloses therein a conventional electronic structure for use in household receiving sets comprising a pairof support wires 4, upper and lower mica an spacer strips 5 and 6, a cathode element I and other conventional elements and leads. The tube alsocomprises a dial illuminating means in the form of an incandescent filament 9, preferably miniature, mounted upon and secured at opposite ends to lead wires In. This filament may be mounted in any suitable manner upon the electronic structure and in the embodiment shown the wires l0 pass through apertures in the insulating spacing member 6 of the tube. The filament 9 is preferably energized from one of the circuits through the several leads and in the embodiment shown is connected in the circuit of the heater element. To this end the leads II are connected at their lower ends to conductors ll, conductors ll being the lead wires for the cathode heater element I! of the tube, thus connecting the filament in parallel with the heater. An anchoring insulating bead ll of glass or the like is fused about the wires III at their point of emergence from the insulating plate 6 on the side of the filament and the wires are bent outwardly above the bead to space the filament 9 away from the electrode assembly of the tube and bring it more closely to the wall of the envelope. Withthis location of the filament 9 possibility of electric or magnetic interference with the functioning of the tube due to the inclusion of the filament within the sealed enclosure of the tube is rendered most remote and r the mounting of the filament on the electronic structure and the disposition shown provide for efficient dial illumination. As the filament is connected across the leads of the heater element l2, current will be supplied thereto when and only when the tube is in operation.

Fig. 3 shows a modification in which the filament 9 is enclosed in an individual bulb I5, thereby enabling the use of a vacuum or gas filling particularly suited to the filament. This bulb may be mounted in any suitable manner, but preferably on the electronic structure, as indicated. As indicated, the lighting filament may be connected in circuit in any suitable manner as, for example, in parallel with the heating circuit or in series with it or otherwise.

A specific embodiment of the invention has now been described in connection with the drawing, illustrating the same as incorporated in a conventional radio tube for radio receiving sets, but it is understood that certain features of the invention are applicable to radio receiving set tubes of other types, and the claims hereto appended are not to be construed as limited to the particular tube herein shown except as may be specifically recited therein.

The following is claimed:

1. The combination with an electronic device comprising a sealed envelope, a plurality of electrodes including a cathode, a heater element for said cathode and conducting leads therefor all enclosed in the envelope, of a filament within said envelope connected in circuit with certain of said lead wires for providing a, source of light during operation of the device.

2. In a radio tube wherein an electronic mount structure having a cathode heater element is contained within a sealed envelope, a miniature incandescent illuminating filament carried by said mount and disposed between the wall of said envelope and said mount, said filament being electrically connected in circuit with said heater element.

3. A radio tube comprising in a sealed envelope an electronic mount structure having a spacer strip and a cathode heater element and a miniature incandescent filament mounted on said spacer strip with the filament mount projecting outwardly from the axis of the tube, and means connecting said filament in the cathode heater circuit.

4. A radio tube comprising in a sealed envelope a pair of spaced support wires, a cathode element, outer and inner spacer strips threaded over said support wires, a heater element for said cathode, a miniature illuminating filament mounted on said inner spacer strip and means connecting the said filament and said heater element in parallel.

5. The combination with a radio tube having a heater element, of a dial illuminating means comprising a filamentary conductor mounted within said tube and connected in the heater circuit so as to be brought to incandescence only during operation of the tube.

6. In combination, a press, conductors sealed in said press and extending therethrough, a plurality of elements carried by said conductors, an insulating spacing member having apertures through which pass said conductors, an incandescible filament, lead wires for said filament passing through said member and connected to two of said conductors intermediate the member and the press, an insulating bead fused to said lead wires between said member and said filament and a sealed envelope secured to said press and enclosing said electrodes, conductors, insulating member and filament, one of said elements being a heater, and said filament lead wires being connected to the conductors for said heater whereby the heater and filament are electrically connected in parallel.

7. In combination with a radio tube of the type having conductors spaced apart and spaced by an insulating member and having a heater ele ment connected across two of said conductors, of a dial illuminating means comprising an incandescible filament positioned above and to one side of said insulating member and electrically connected in parallel with the heater element, said filament being supported by a pair of lead wires passing through said insulating member and connected to the conductors for the heater element and by an insulating bead fused to said lead wires above said insulating member. said lead wires above said bead being bent outwardly away from said spaced conductors to bring the filament out of the active zone of the tube.

8. In an electronic device of the character set forth in claim 1 wherein the filament is mounted upon the electronic structure and is contained within an individual bulb isolating the filament from the envelope space.

9. In an. electronic device of the character set forth in claim 1 wherein the filament is mounted upon the electronic structure and is exposed to the vacuum conditions of the envelope.

10. A radio tube of the character set forth comprising an electronic. structure having a cathode housed within a sealed envelope and a filamentary illuminating means contained within said envelope and disposed out of heat exchange relation with said cathode.

MILTON R. SCHULTE. 

